Hi David- I got a big speed increase out of moving from 6 GB to 12 when dealing with really large files on my Mac Pro tower. At least in the US, Apple is the most expensive possible place to buy RAM (as much as 5 times as expensive as other suppliers) - the Mac Pro is very easy to add RAM to, so buy it from Apple with the minimum amount of RAM (1 or 2 GB) you can get and add extra RAM yourself. US prices are as low as $59 for a 2 GB FBDIMM (the Mac Pro takes RAM in sets of four, so you can add 8 GB for USD 240 or go all the way to 16 (removing all existing RAM) for $480. I don't know if Apple Australia will sell you a Pro with only 1 GB of RAM (they did here when I bought mine), but that's the best way to go, because you are paying Apple's extortionate RAM prices for as little as possible, and buying all your RAM from a better-priced supplier. Also beware of a possible impending upgrade to the Mac Pro tower in March. They may introduce a faster one, and when they do, the price on the current (already very fast) model will go way down. I'd wait to see what happens next month if you can, then either buy a faster machine for the same price or get a great deal on the current model.

When it comes to towers I buy the lowest speed processor available with the basic package ( no extras at Apple ) and then MAX out the RAM from a private vendor its easy to install yourself. In my experience this leaves me with a powerhouse that works three times faster than the previous outdated models even the TOP processor speed with canned RAM. As a rule of thumb you want to at least double the min requirements from your most power robbing software. Keep in mind just becasue a software specs a minimum memory level that only applies to that software. AS soon as you run more than one application at once you run into trouble as that app now needs memory too and will start giving you the spinning wheel of death and possibly crash your apps especially PS its a very power robbing app. That said Maxxing out your RAM is always advisable if $$$ allows it. Nothing will make your machine run smoother and faster.

By the way dont buy RAM from Apple EVER! Complete rip off. Try these guys I highly recommend they are speedy, knowledgeable, reliable, and ship worldwide.

A good rule of thumb for Macs is to stuff them with as much RAM as they can take. The exception here is perhaps the Mac Pro which can take 32Gigs, which is a lot and is somewhat expensive. But that said, 16G kits are relatively inexpensive (~~$600) and a great place to be. And definitely, don't pay the ridiculous price for Apple RAM -- there are plenty of good alternatives and I have been very happy with OWC: http://eshop.macsales.com/shop/apple/memory/ I am running 6 gigs of their memory in my 15" MBP and 16 gigs in my Mac Pro.

No huge rush if it means getting the older one cheaper or a new model for the same price..

*IF* there is a new Mac Pro on the horizon, it will be at least 6 months and probably a year before you see it on the shelves. Regardless, when it comes out, you can expect a 15% discount on the current models, and the new ones released at about the same pricepoint as the current ones. More to the point I think is that software is still *wayyyyy* behind the abilities of the current system and still behind even the previous 8-core Mac Pro system

Also beware of a possible impending upgrade to the Mac Pro tower in March. They may introduce a faster one, and when they do, the price on the current (already very fast) model will go way down. I'd wait to see what happens next month if you can, then either buy a faster machine for the same price or get a great deal on the current model.

If I had jumped in a couple weeks back I might have cause to take you off the christmas card list ..

Well in fairness to me, it still remains to be seen exactly how much faster the new 8-core 2.93 is compared to the older 8-core 3.2 machine with real-world apps we all use like CS4, C1, Lightroom, etc. Even Apple's own specs only show a 20% increase with Aperture, and I still need to see that hold while processing a bunch of really large files, and CS4 is so poorly coded for new machines I expect even less of a gain with it. I also am curious about drive I/O for a bunch of larger files -- is it still going to be the major bottleneck? Probably... For sure the new DDR3 RAM is going to help a lot, the fact that the new chip -- at least the 2.93 -- will automatically over-clock itself to 3.33 on non-multi-core processes is very cool. However, comparing prices you can save about $2000 buying the older 8-core 3.2 machine, and $2000 buys a lot of drives, cards, cables, external boxes and ram...